My suggestions remain the same.
Three things will help. First, at the least sign of one of these episodes at schoolo he should be placed in time out. Second, he should be observed by a behavioral health specialist at school in order to clarify the nature of his reactions and how to intervene beyond the time out response. Third, he should undergo a comprehensive Speech/Language evaluation.
I noticed at the age of 3 that my son had an advanced sense of humor. He understood a lot of jokes even then. He seems to have an advanced memory. He can count in Japanese and Spanish. He applies learned information and is not just regurgitating. He recognizes many sight words that children older than him don't. I have a feeling he may be bored in his Kindergarten class doing repetitious activities about colors, shapes, and numbers that he already knows. I don't believe he is able to voice this appropriately thusly causing him to act out. His speech needs work, however his ability to learn and apply information is bar none. I find that he needs much stimulation because he asks questions about everything. What do you think?